Multi-directional Impact Research Articles

Government Financial Asset and Debt Management: Identifying Effective Indicators

High risks, their multifactorial nature, multidirectional impact, and suddenness of occurrence due to the deep mutual integration of most national economies force looking for ways to modernize the government financial assets and liabilities management in special economic conditions, which would allow to increase its mobility and adaptability.

Microstructure, texture evolution and yield strength symmetry improvement of as-extruded ZK60 Mg alloy via multi-directional impact forging

Multi-direction impact forging (MDIF) was applied to the as-extruded ZK60 Mg alloy, and the microstructure, texture evolution and yield strength symmetry were investigated in the current study. The results showed that the average grain size of forged piece was greatly refined to 5.3 µm after 120 forging passes, which was ascribed to the segmenting effect of {10–12} twins and the subsequent multiple rounds of dynamic recrystallization (DRX). A great deal of {10–12} twins were activated at the beginning of MDIF process, which played an important role in grain refinement. With forging proceeding, continuous and discontinuous DRX were successively activated, resulting in the fully DRXed microstructure. Meanwhile, the forged piece exhibited a unique four-peak texture, and the initial <10−10>//ED fiber texture component gradually evolved into multiple texture components composed of <0001>//FFD (first forging direction) and <11–20>//FFD texture. The special strain path was the key to the formation of the unique four-peak texture. The {10–12} twinning and basal slip were two dominant factors to the evolution of texture during MDIF process. Grain strengthening and dislocation strengthening were two main strengthening mechanisms of the forged piece. Besides, the symmetry of yield strength was greatly improved by MDIF process.

СТРУКТУРНЫЕ СДВИГИ В НАЦИОНАЛЬНОЙ И РЕГИОНАЛЬНОЙ ЭКОНОМИКЕ: ИСТОРИЧЕСКИЙ ПОДХОД (НА ПРИМЕРЕ АВИАСТРОИТЕЛЬНОЙ ОТРАСЛИ)

The article is devoted to the study of the factors of structural changes in the economy of regions. There is no doubt that the current socio-economic and political situation, which has been formed as a negative result of the consequences of the COVID-19 epidemic, provides a rather negative impact on the economy of regions. In particular, competition for resources and potential sales markets is sharply increasing. The article presents the point of view of the author on the factors of development of the regional economy and structural changes that can have a multidirectional impact on the economy of a region. It is noted that a coherent theory of structural changes has not yet been developed, which makes it difficult to conduct an objective analysis of the causes and consequences of structural changes in the regional economy. The conclusion about a strict correlation be-tween the generation of new knowledge, which leads to all kinds of innovations, and struc-tural changes in the regional economy is substantiated. At the same time, the innovation process is characterized by a high level of uncertainty in terms of obtaining the desired end results. Specific historical examples of the impact of innovation on the development of the regional economy are considered. It is especially noted that the technological lag can last for decades, having the most negative impact on the socio-economic situation in the region. The conclusion that innovations can contribute to the development of economical-ly weak regions is substantiated.

Public involvement in risk governance in the internet era: impact of new rules of building trust and credibility

The article draws attention to the multidirectional impact of the widespread Internet communication on public involvement in risk governance processes. The prevalence of Internet communication changes the rules of building credibility and trust, and a position of expert knowledge. As online peer-to-peer information are not verified by any single trustworthy institution, the expert community often perceives it as a source of disturbance in risk governance. We refuse to frame online communication simply in terms of a threat to responsible dealing with risks and, instead, demonstrate how it creates new conditions for public involvement in risk governance, which may strengthen or hamper responsible risk governance, potentially compensating for the shortcomings of the system based solely on state agencies’ activities. Basing on the qualitative analysis of three critical cases, we show how the involvement of Internet-enabled groups impacts the risk governance of specific issues in Poland. Specifically, the Internet-enabled participation amplifies evidence-based concerns (the case of city air pollution), signals new “unknown unknowns” (the case of fracking), or weakens procedures based on the body of scientific knowledge (the case of vaccination controversy). To decide when and how to harness the potential of internet-enabled public involvement and when to focus on limiting the harms it may engender, we propose a framework that takes into account the level of uncertainty, the extent to which risk mitigation policy in place reflects the scientific consensus (if there is one), and the accepted rules of credibility and trust by Internet-enabled groups to expert knowledge. We claim that risk governance processes should routinely involve analyses and actions aimed at governing risks that ignore the impact of widespread Internet use may prove counter-effective.

THE IMPACT OF TYPE 2 DIABETES ON THE CARDIOVASCULAR SYSTEM IN MALE AND FEMALE RATS

Introduction. Type 2 diabetes mellitus is one of the main factors of the cardiovascular risk, which leads to a disproportionate increase in cardiovascular events in women and men. While the greater excess risk of diabetic vascular complications in women compared with men has been described, mechanisms underpinning the sex difference have not been identified in full. The aim of this study was to determine the impact of type 2 diabetes (T2D) on the functional state of the cardiovascular system in male and female rats. Materials and Methods. T2D was induced in male and female Wistar rats by a high-caloric diet during 14 weeks combined with intraperitoneal injections of 25 mg/kg streptozotocin twice per week. At the end of the study electrocardiograms were recorded in leads II. A comparative analysis of changes in the functional state of the heart in male and female rats with experimental T2D was conducted. Results. It was established that T2D, independently of gender, results in the formation of pathologically accelerated rhythm and sinus tachycardia in experimental animals. Experimental T2D led to the prolongation of the systole in rats of both sex and decreasing of R-wave voltage in males in comparison with control group. In addition, T2D was accompanied by multidirectional impact on the atrial function in the heart of both sexes: P wave’ amplitude was increased in females while it was decreased in males, what can indicate either right or left atrial enlargement. It was found that T2D promotes the development of myocardial diastolic dysfunction in females, in contrast to males, which was confirmed by prolongation of T-P interval and a decrease of amplitude and duration of the T wave in comparison with intact female rats. Conclusions. T2D, independently of gender, caused cardiac arrhythmias, functional changes in atrial and ventricular conduction, but only in females, in contrast to males, was accompanied by the development of myocardial diastolic dysfunction. This data justify the necessity of personalized- and gender-specific therapy development for the prevention and management of diabetic cardiovascular complications.

Методические подходы к оценке влияния импортозамещения на экономический рост

Import substitution provide multidirectional impact on the economy, accompanied by both positive and negative effects, nevertheless, import substitution, is a leading tool to overcome most unfavorable events in the country's economic system, which extremely aggravated in the first half of 2020. It is possible to force the development of import substitution's positive effects if there is a clear quantitative assessment of its effectiveness in terms of its impact on the growth of the Russian economy. &#x0D; Based on a generalization and analysis of the methods and tools for assessing the impact of import substitution on the economy used by domestic and foreign authors in their studies, scientific-methodological approaches to such an impact were identified. In model approach, an author’s assessment methodology has been developed. At the first stage using an expanded system of import substitution effectiveness indicators, which grouped by sectors of the economy, a composite indicator of the effectiveness is formed by means of principal components method. At the second stage the dependence of economic growth on a composite indicator of import substitution effectiveness is formed by means of correlation and regression analysis. &#x0D; General government of the economy can use our technique to shape an economic development strategy under the import substitution.

Challenges of oral medicine specialists at the time of COVID-19 pandemic.

Challenges of oral medicine specialists at the time of COVID-19 pandemic.

Microstructure and texture optimization by static recrystallization originating from {10-12} extension twins in a Mg-Gd-Y alloy

During the deformation of Mg alloys, {10–12} extension twin often contributes to the formation of basal texture but rarely assists the nucleation of recrystallization, i.e., effective grain refinement, therefore it seems to make against the improvement of formability and mechanical properties. In this work, {10–12} extension twin has been creatively utilized as a preference nucleation site for static recrystallization (SRX), achieving grain refinement and orientation randomization in a Mg-Gd-Y alloy using multi-directional impact forging (MDIF) and subsequent annealing treatment. Effect of {10–12} extension twin on SRX behavior has been investigated by annealing treatment at 450 °C using quasi-in-situ optical microscopy (OM) and quasi-in-situ electron back-scattering diffraction (EBSD). The microstructural evolution during annealing shows that several SRX gains can nucleate from the grain boundary of untwinned grains, but they only have few influences on the final microstructure due to their limited volume faction and sluggish growth. In contrast, a large number of SRX gains can initiate from {10–12} extension twin and grow up without the confine of twin boundaries. Finally, they consume their parent grains and make the main contribution to grain refinement. This should be attributed to those pinned {10–12} twin boundary, by interacting with various dislocation slips during the MDIF process, which can operate like grain boundary, store enough strain energy, and promote the nucleation of SRX during annealing. On the other hand, SRX grains usually keep initial random orientation and further randomize the forging texture during annealing treatment.

The Impact of Mutations in the HvCPD and HvBRI1 Genes on the Physicochemical Properties of the Membranes from Barley Acclimated to Low/High Temperatures.

(1) Background: The study characterized barley mutants with brassinosteroid (BR) biosynthesis and signaling disturbances in terms of the physicochemical/structural properties of membranes to enrich the knowledge about the role of brassinosteroids for lipid metabolism and membrane functioning. (2) Methods: The Langmuir method was used to investigate the properties of the physicochemical membranes. Langmuir monolayers were formed from the lipid fractions isolated from the plants growing at 20 °C and then acclimated at 5 °C or 27 °C. The fatty acid composition of the lipids was estimated using gas chromatography. (3) Results: The BR-biosynthesis and BR-signaling mutants of barley were characterized by a temperature-dependent altered molar percentage of fatty acids (from 14:0 to 20:1) in their galactolipid and phospholipid fractions in comparison to wild-type (WT). For example, the mutants had a lower molar percentage of 18:3 in the phospholipid (PL) fraction. The same regularity was observed at 5 °C. It resulted in altered physicochemical parameters of the membranes (Alim, πcoll, Cs−1). (4) Conclusions: BR may be involved in regulating fatty acid biosynthesis or their transport/incorporation into the cell membranes. Mutants had altered physicochemical parameters of their membranes, compared to the WT, which suggests that BR may have a multidirectional impact on the membrane-dependent physiological processes.

Design method for a bionic wrist based on tensegrity structures

The traditional bionic upper limb structure design is limited by the motion pair and cannot guarantee the flexibility of the mechanical structure. The tensegrity structure has the characteristics of high deformability, strong self-adaptability, and resistance to multi-directional impact. According to the biological characteristics of the upper limbs of the human body, an anatomical study is performed on the upper limb wrist joints that achieve adduction/abduction, flexion/extension, to obtain the relationship between the movements of the related bones and muscles, and to simplify the shape and structure of the wrist. Equivalent mapping of a mechanical model based on two-bar tensile properties. Through the contraction and stretching of the spring, the movement characteristics of the human muscles are realised, and the optimised bionic upper limb wrist tensioning robot without motion pair is further obtained. Adams simulation is used to verify that the bionic tensile wrist can simulate the change movement of the human wrist. The experimental platform was built and a physical prototype was made and the prototype was tested. The results show that the bionic tensile wrist can realise the adaptive motion characteristics of the human wrist well and stably, which proves the validity and feasibility of this design method.

Reasonable utilization of {10-12} twin for optimizing microstructure and improving mechanical property in a Mg-Gd-Y alloy

During the deformation of Mg alloys, {10-12} extension twin, as one of the most active deformation mechanisms, contributed much to the formation of basal texture, yet little to dynamic recrystallization (DRX) grains, i.e., effective grain refinement. In this work, {10-12} extension twin had been creatively utilized to achieve grain refinement and property improvement in a Mg-Gd-Y alloy by multi-directional impact forging (MDIF). Firstly, flourishing {10-12} extension twins divided the parent grain into many fine independent regions (~10 μm). Meanwhile, a large number of twin boundaries were pinning mainly by interaction with neighboring dislocations in twin or matrix. Secondly, those pinned twin boundaries can effectively accumulate dislocation slips and promote the formation of extensive low angle grain boundaries (LAGBs). These high densities of LAGBs can further subdivide the independent regions provided by extension twins into micro-regions (~5 μm). Thirdly, those fine micro-regions developed to be DRX after a dynamic recovery. Finally, we obtained a yield isotropy high-strength Mg alloy with an ultimate tensile strength of 354 MPa after MDIF of 110 passes. This work proposed a brand new insight to prepare wrought Mg alloy with fine grain, yet without strong texture, which is beneficial to better formability and mechanical property isotropy.

ВПЛИВ ЕНДОГЕННИХ ПРОСТАНОЇДІВ НА ЖОВЧОСЕКРЕТОРНУ ФУНКЦІЮ У ЩУРІВ РІЗНИХ ВІКОВИХ ГРУП

In acute experiments on different age group of 30 white wild-type rats: juvenile (weight 130–175 g), mature (weight 200–250 g) and old (weight 300 g and more) we were investigated the changes in the volume rate of bile secretion with cyclooxygenase inhibition by acetylsalicylic acid (100 mkg/kg weight of animal) which is a blocker of the prostaglandin synthesis enzyme. We explored the changes of the level of choleresis and bile biochemical components by thin-layer chromatography In vivo. The relative abundances of cholecycle, henodeoxycholic, taurocholic and glycocholic bile acids in the liver of rats were determined by chromatography, with the subsequent densitometry. The biliary acid flow rate was calculated as the sum of the bile acid concentration multiplied by the volume of secreted biliary in one relevant thirty-minute sample. The conjugation coefficients were calculated for each thirty minute sample. Reduction of bile secretion by endogenous prostanoids was shown, because inhibition of prostaglandins synthesis caused the hypercholeresis on 42–112,5 % in different rat age groups, compared to control. Endogenous prostaglandins suppressed the processes of conjugation in old and juvenile age group on 117–189,1 %, in contrast these regulators have no significant effect on bile acids association with glycine and taurine in mature rats. The binding of endogenous prostanoids probably increased the conjugation processes in juvenile rats, whereas in the old experimental group acetylsalicylic acid was significantly reduced by 123 % on average. Analysis of changes in free and conjugated bile acids in the rats of different age groups showed that the ratio of qualitative changes in structure of the liver bile in rats with the cyclooxygenase blockade is mainly due to enhanced synthesis of free bile acids de novo. Therefore, endogenous prostanoids affect in the opposite way. There are have multi-directional impact on bile secretion in different age groups of rat that means ambiguous role of these drugs in liver function regulation at different stages of ontogenesis.

Temperature Effects on the Microstructures of Mg–Gd–Y Alloy Processed by Multi-direction Impact Forging

A high strain rate multi-directional impact forging (MDIF) was applied to a solutionized Mg–Gd–Y–Zr alloy in the temperature range of 350–500 °C. Results demonstrate that the dominant deformation mode is twinning at a temperature below 400 °C, whereas at a medium temperature of 450 °C considerable continuous dynamic recrystallization was promoted by {10–12} extension twins. At a higher temperature of 500 °C, twinning activation was suppressed. New DRX grains were observed but their sizes were much bigger than those resulting from the MDIFed 50 passes at 450 °C, which are ascribed to the larger grain boundary mobility and atomic diffusion at 500 °C. Moreover, a non-basal weak texture was gained afterward MDIF at each temperature, which is credited to the MDIF process and the minor strain applied in each pass.

Study on the Damage Mechanism of TiN/Ti Coatings Based on Multi-Directional Impact

TiN/Ti coatings have great application potential in improving aero-engine server lives in a dusty environment. However, the damage behavior and mechanism of the coating and substrate under high impact speed and multi-direction loading conditions has scarcely been investigated. In this paper, TiN/Ti coatings were deposited on Ti6Al4V alloys by a magnetic filter cathode vacuum arc. Multi-directional impact tests were carried out by a gas gun system at, 45°, 60°, and 90° with a velocity of 330 m/s. The damage behaviors and mechanisms of the TiN/Ti coatings were investigated and revealed by researching the damage morphology, crack propagation, and stress distribution. The results show that plastic deformation occurs both in the coatings and the substrates under high speed impacting. Cracks extend vertically downward in the TiN layer first and are deflected at the Ti layer when the driving force is not enough. Circular cracks and radical cracks are found to form network cracks on the surface of the coating and the shear stress loaded by the particles, which drives cracks’ propagation is the main reason for the peeling off on the coatings.

Static recrystallization behavior of multi-directional impact forged Mg-Gd-Y-Zr alloy

The static recrystallization behavior of a (Mg-9.02Gd-4.21Y-0.48Zr wt.%) GW94 alloy during annealing treatment in the temperature range of 350–500 °C has been investigated by means of electron backscattered diffraction (EBSD). To investigate the role of twin boundaries in static recrystallization of GW94 alloy, a large number of {10–12} extension twins were introduced initially by multi-directional impact forging (MDIF) process. After the MDIF process, coarse grains containing parallel and intersected twins while small grains containing only parallel twins were observed. It has been observed that twin/grain boundaries (TBs/GBs) are stable at 350 °C, but static recrystallization governed by the increased twin/grain boundary mobilities begins at the 400–450 °C temperature range. Microstructure evolution during static annealing reveals that nearly all pre-existing {10–12} extension twins start to recrystallize at 400 °C and 60 min, yet few parallel twins plus residual twin traces with misorientations of 5°–10° were observed. In contrast to the parallel twins in both large and small grains, the intersected {10–12} extension twins in coarse grains were found to be unstable and more effective to induce recrystallization.

Feasibility of using a novel instrumented human head surrogate to measure helmet, head and brain kinematics and intracranial pressure during multidirectional impact tests

ObjectivesAim of the work is to present the feasibility of using an Instrumented Human Head Surrogate (IHHS-1) during multidirectional impacts while wearing a modern ski helmet. The IHHS-1 is intended to provide reliable and repeatable data for the experimental validation of FE models and for the experimental evaluation of modern helmets designed to enhance the degree of protection against multidirectional impacts. DesignThe new IHHS-1 includes 9 triaxial MEMS accelerometers embedded in a silicone rubber brain, independently molded and presenting lobes separation and cerebellum, placed into an ABS skull filled with surrogate cerebrospinal fluid. A triaxial MEMS gyroscope is placed at the brain center of mass. Intracranial pressure can be detected by eight pressure sensors applied to the skull internal surface along a transversal plane located at the brain center of mass and two at the apex. Additional MEMS sensors positioned over the skull and the helmet allow comparison between outer and inner structure kinematics and surrogate CSF pressure behavior. MethodsThe IHHS-1 was mounted through a Hybrid III neck on a force platform and impacted with a striker connected to a pendulum tower, with the impact energies reaching 24J. Impact locations were aligned with the brain center of mass and located in the back (sagittal axis), right (90° from sagittal axis), back/right (45°), and front right (135°) locations. Following dynamic data were collected: values of the linear accelerations and angular velocities of the brain, skull and helmet; intracranial pressures inside the skull. ResultsDespite the relatively low intensity of impacts (HIC at skull max value 46), the skull rotational actions reached BrIC values of 0.33 and angular accelerations of 5216rad/s2, whereas brain angular acceleration resulted between 1,44 and 2,1 times lower with similar values of BrIC. ConclusionsThe IHHS-1 is a physical head surrogate that can produce repeatable data for the interpretation of inner structures behavior during multidirectional impacts with or without helmets of different characteristics.

Grain Refinement Mechanism and Microstructural Evolution of M50NiL Steel during Multi-directional Impact Forging

This study investigated the effect of varying temperatures and cumulative strains on M50NiL steel during multi-directional impact forging (MDIF). The grain size was found to increase gradually with increasing temperature, after being held at 1050, 1100, 1150 and 1180 °C for 30 min, with the minimum grain size observed at 1100 °C during the MDIF process. The M50NiL steel subjected to MDIF at 1100 °C and at varying cumulative strains of 0.6, 1.8, 3.6 and 7.2 exhibited grain sizes that decreased with increasing cumulative strain. The mean grain size gradually decreased to ~ 1 μm at a cumulative strain of 7.2. New small grains were nucleated at grain boundaries via dynamic recrystallization, and microbands were formed via the temperature drop during the continuous forging process. The grains were subdivided into subgrains by the microbands, and these subgrains were converted to new refined grains via transformation of their boundaries into high-angle boundaries. Further, martensite transformation was restrained owing to the grain refinement. Improved tensile strengths values are obtained after MDIF process.

Effective Contract and Motivation: Can Reforms Improve the Work of Russian Doctors?

Since 2012 the reform of the salary system of workers in the budgetary sphere, called the introduction of an effective contract, has been implemented in Russia. The paper presents the results of a study of the reform impact on the labor motivation of physicians. Empirical data are obtained by conducting in-depth interviews with physicians and heads of state medical institutions in Moscow and one of the regions in the European part of the country in 2016. The study revealed multidirectional impact for physicians’ readiness to work more and better by effective contract. There are three groups of doctors. The first and largest group: physicians who feels a positive impact of motivation incentives for physicians’ motivation at work. The second group: physicians who are convinced that an effective contract does not affect their motivation. The third group: physicians who believe that effective contract has led to a weakening of physicians’ motivation. The article gives an explanation of the results of the study. Results of the study also clearly show that the changes in the physician’s remuneration system aimed exclusively on the growth of salary of doctors are necessary, but not sufficient. The impact of an effective contract on the achievement motivation (the desire to improve their professional capabilities and results) was different for experienced and young doctors. The most pronounced increase in the achievement motivation was observed for the majority of young doctors. A special part of the research paper is devoted to informal payments which influence physicians’ motivation. The research has shown that these payments may smooth motivational effect caused by the new rules of remuneration. This fact is typical for Moscow, while in the region, this effect is not clearly expressed.

Medical Tourism: Its Role in Maintaining Health and Increasing Life Expectancy

The subject of the research is development of medical tourism as a measure of maintaining health and increasing life expectancy of the population. The relevance of the study is substantiated by decisions on increasing the retirement age, which requires improving working conditions and arrangement of high-performance jobs as components of the social policy aimed at increasing life expectancy and improving the quality of life as the most important conditions for ensuring sustainable economic development of the country. The purpose of the research was to determine the role of medical tourism in maintaining physical strength, increasing the lifetime and maintaining the health of the population in line with the key national goal of accelerating the national economy growth rates. Based on official statistical and audit information and expert opinions, the paper discusses specific features and practices of organizing medical tourism, analyzes the current state and identifies factors that have a multidirectional impact on its development. It is concluded that the necessity to take into account the specific conditions of the spatial development strategy of the Russian Federation orients companies engaged in medical tourism towards expanding the range and improving the quality of services provided. The proposed measures aimed at perfection of the methodological principles and tools of research can be used at the regional level to justify the creation of tourist clusters. Proposals for the development of marketing are aimed at improving the financial sustainability of companies and recommended for taking into account by the top management of medical tourism companies.

Evaluation of a novel bicycle helmet concept in oblique impact testing

BackgroundA novel bicycle helmet concept has been developed to mitigate rotational head acceleration, which is a predominant mechanism of traumatic brain injury (TBI). This WAVECEL concept employs a collapsible cellular structure that is recessed within the helmet to provide a rotational suspension. This cellular concept differs from other bicycle helmet technologies for mitigation of rotational head acceleration, such as the commercially available Multi-Directional Impact Protection System (MIPS) technology which employs a slip liner to permit sliding between the helmet and the head during impact. This study quantified the efficacy of both, the WAVECEL cellular concept, and a MIPS helmet, in direct comparison to a traditional bicycle helmet made of rigid expanded polystyrene (EPS). MethodsThree bicycle helmet types were subjected to oblique impacts in guided vertical drop tests onto an angled anvil: traditional EPS helmets (CONTROL group); helmets with a MIPS slip liner (SLIP group); and helmets with a WAVECEL cellular structure (CELL group). Helmet performance was evaluated using 4.8 m/s impacts onto anvils angled at 30°, 45°, and 60° from the horizontal plane. In addition, helmet performance was tested at a faster speed of 6.2 m/s onto the 45° anvil. Five helmets were tested under each of the four impact conditions for each of the three groups, requiring a total of 60 helmets. Headform kinematics were acquired and used to calculate an injury risk criterion for Abbreviated Injury Score (AIS) 2 brain injury. ResultsLinear acceleration of the headform remained below 90 g and was not associated with the risk of skull fracture in any impact scenario and helmet type. Headform rotational acceleration in the CONTROL group was highest for 6.2 m/s impacts onto the 45° anvil (7.2 ± 0.6 krad/s2). In this impact scenario, SLIP helmets and CELL helmets reduced rotational acceleration by 22% (p = 0003) and 73% (p < 0.001), respectively, compared to CONTROL helmets. The CONTROL group had the highest AIS 2 brain injury risk of 59 ± 8% for 6.2 m/s impacts onto the 45° anvil. In this impact scenario, SLIP helmets and CELL helmets reduced the AIS 2 brain injury risk to 34.2% (p = 0.001) and 1.2% (p < 0.001), respectively, compared to CONTROL helmets. DiscussionResults of this study are limited to a narrow range of impact conditions, but demonstrated the potential that rotational acceleration and the associated brain injury risk can be significantly reduced by the cellular WAVECEL concept or a MIPS slip liner. Results obtained under specific impact angles and impact velocities indicated performance differences between these mechanisms. These differences emphasize the need for continued research and development efforts toward helmet technologies that further improve protection from brain injury over a wide range a realistic impact parameters.